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View Full Version : I gots a boat quershun for you engineer types........



Big Muddy
07-13-2014, 06:19 PM
My Tahoe Q7i, that I got for the grandkids, "wanders", for lack of a better term, both left and right, when underway at idle speed....it is not a problem, when underway and on plane, however.

It's a pain in the azz, when trying to center the boat onto the storage ramp, or when trailering the boat onto the trailer rails.

I asked my dealer about it, and he said that is a "phenomenon" of V-hull boats because at slow speeds, the boat can't decide which way it wants to go, when the V-hull is cutting thru the water....therefore, it "wanders" left, momentarily, then right, momentarily....I'm a bit skeptical about that explanation, and even if that's the case, surely, there's a fix for it, in this day and age!!!

Any boating experts know about this???

Captain
07-13-2014, 06:29 PM
I had the same problem running a friends boat and he told me to trim down and it did help a lot. Here is something I found. http://www.boatingmag.com/controlling-low-speed-wander

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BarryBobPosthole
07-13-2014, 06:46 PM
Yep. What Captain said. Trim it down to push the nose further down. Trim tabs might help. Otherwise go faster or ignore it. Not much else to do.
BKB

Arty
07-13-2014, 07:12 PM
I third that. My Maxum 1900SR does the same thing. Trim all the way down.
And small corrections on the wheel vs wild motions port and starboard.

Thumper
07-13-2014, 08:24 PM
Yeppers, what they said. If'n ya' gots kids in the boat ... move 'em to the front for a bit more slow speed control. I used to go to an area here called the "Chain-of-Lakes" which is a whole bunch of lakes connected by canals. Those canals were "idle speed only". I looked like a dang drunk trying to negotiate some of the longer, narrow, canals and I was like a living pinball machine going from one side of the canal to the other! It was embarrassing when I'd meet a boat coming the other way.

I had the most fun trying to switch from outboards to jets. It's hard to get in the habit of throttling UP when "slowing down" coming to the dock or trailer etc. No throttle = No control. I couldn't tell you how many docks I slammed into before I got the hang of it. :eek:

Big Muddy
07-14-2014, 12:48 AM
Glad I'm not the only one with a "wandering" boat....and, I've already tried all suggestions....trimmed all the way down, moved the kids up front, small steering corrections, even filled fuel tank to only half full....nothing cures it, but trimming all the way down does seem to help a little bit.

Guess I'll just hafta live with it.

Thumper
07-14-2014, 12:58 AM
Yep, it's the nature of the beast and you're not alone. What I don't understand is that some v-hull boats don't do it (or it's barely noticeable) and others are a beast to handle at idle speed. I'm not sure what the difference is between hulls, bit they sure do vary a lot between manufacturers.

Big Muddy
07-14-2014, 01:40 AM
My Tahoe inboard motor didn't come with a trim tab installed.....dealer says they aren't needed on power steering.

When I say "trim tab", I'm talking about the small tab which bolts on, under the cavitation plate, right above the prop(see photo)....not the other type of trim tabs.

Just wondering, if one of the trim tabs might help, too.

3284

Arty
07-14-2014, 06:49 AM
I have one of those in my outdrive (inboard motor, no power steering)
YES. Id say it would help.

BarryBobPosthole
07-14-2014, 08:04 AM
You can try monkeying with it but I don't think it'll do much. Its actuallyban anode if its what I'm thinking of and is more important When you're on the coast somewhere. The trim tabs I'm thinking of are plates that go on the left and rightvofvthe transom at the water linecand you can lower them and they'll push your nose down basically. Prevent porpoising at lower speeds too.

BKB

Big Muddy
07-14-2014, 08:27 AM
Yep, Phole, those are the trim tabs that I'm NOT referring to....what I'm referring to, is called a trim tab, too....and, it actually serves a dual purpose, depending on the material that it's made of....it can be made of an anode(sacrificial zinc) material, but it is used to trim the boat, also, by reducing the torque effect of the prop.

https://www.youtube.com/watch?v=DplBwb-CnQk

BarryBobPosthole
07-14-2014, 08:33 AM
I've played with the tab on my lower unit (that sounds kinda dirty don't it) and it never made much difference. I had an old 65 Johnson on one of my boats many years ago and it would really produce a lot of torque on the steering and I recall adjusting that tab and it helped some. I don't think it'd do anything for the wallering you're talking about though because that's caused more by the keel than it is the motor. At least I think it is.

BKB

Thumper
07-14-2014, 08:53 AM
What model year was "The Big White Johnson" P-hole?

Arty
07-14-2014, 09:04 AM
Eddie,
I don't believe that tab is too expensive. If you've got a place on your outdrive to put it ( I'm guessing you have an alpha 2 outdrive) then stick it on there. I betchya it'll help.

BarryBobPosthole
07-14-2014, 09:05 AM
It was an 84 Ranger. The old Johnson I'm talking about was on the Leakin' Lena. A 65hp 'Stinger it was called. Great little engine. In fact the engine was in ten times better shape than the boat. I wish I'd kept that motor and gave it to Bob for his old boat at the time. I ended up giving that boat and motor to someone.

BKB

DeputyDog
07-14-2014, 09:07 AM
My old Larson bow-rider does the same thing. It's not too bad, but it does make it interesting when you're in a narrow channel and meet someone. If I'm out in the open, if I just let it go, it goes back and forth without making any corrections. I'dl always wondered about that too, but just lived with it.

This is just another reason why I hang out with you all here. I learn a lot from you.

Big Muddy
07-14-2014, 09:25 AM
Eddie,
I don't believe that tab is too expensive. If you've got a place on your outdrive to put it ( I'm guessing you have an alpha 2 outdrive) then stick it on there. I betchya it'll help.

Yep, Arty, my cavitation plate DOES have a place to install a trim tab....I looked it up, and they're only $15.99....can't hurt anything, and easy to install, so I'm gonna try it.

johnboy
07-14-2014, 11:01 AM
The little tab on the cav plate is to counteract torque steer from the engine when on plane. It should be adjusted so you aren't having to put countersteer in to have the boat go straight when at speed. It won't do diddly when just putting along.

As has been said, low speed wander is really a hull issue and there isn't much you can do about it other than what has been mentioned. My friend has a 28' cruiser with a deep V, full planing hull and it is a real beast when doing any slow stuff. Talk about a drunken sailor!

LJ3
07-14-2014, 12:42 PM
We call it "plowing" in my neck of the woods and it's just part of the V hull experience.